<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Document</title>
    <style>
        html,
        body {
            margin: 0px;
            width: 100vw;
            height: 100vh;
        }

        main {
            height: 100vh;
            display: grid;
            grid-template-columns: 200px auto 200px;
            grid-template-rows: 80px 30px auto 40px;
            grid-template-areas: "header header header" "caidan caidan caidan" "zuo zhong you" "footer footer footer";
        }

        .header,
        .caidan,
        .zuo,
        .zhong,
        .you,
        .footer {
            border:1px solid #ccc
        }

        .header {
            grid-area: header;
        }

        .caidan {
            grid-area: caidan;
            background-color: aqua;
        }

        .zuo {
            grid-area: zuo;
            float: left;
           
            
            
            

        }

        .zhong {
            grid-area: zhong;
        }

        .you {
            grid-area: you;
        }

        .footer {
            grid-area: footer;
        }
        .caidan_li{
            float: left;
            text-align: center;
            width: 120px;
            height: 25px;
            font: bold 14px/20px '宋体';
            border-left: 2px solid red;
            list-style: none;
            margin: px 0px;
            
        }
        .caidan_ul{
            padding-left: 0px;
            -webkit-margin-start: 5rem;
            -webkit-margin-before:4px;
            -webkit-margin-after:0rem;
            
        }
        .caidan_li nav:hover{
            cursor: pointer;
        }
        .caidan_li:last-child{
    border-right:2px solid red;
}

        

 #nav {
            width: 150px;
            height: 40px;
            float: left;
            margin: 0 auto;
        }

        ul {
            list-style: none;
        }

        ul li {
            line-height: 40px;
            text-align: center;
            position: relative;
        }

        a {
            text-decoration: none;
            color: #000;
            display: block;
            padding: 0 10px;
            height: 40px;
        }

        a:hover {
            color: #fff;
            background-color: #000;
        }
.aaa 
li{
    background-color: rgb(255, 130, 10);
}
        ul li ul li {
            float: none;
            background-color: #eee;
            margin-top: 2px;
            
        }

        ul li ul {
            position: absolute;
            left: 50px;
            top: 20px;
            display: none;
        }

        ul li ul li a {
            width: 80px;
        }

        ul li ul li a:hover {
            background-color: #06f;
        }

        ul li:hover ul {
            display: block;
        }
    </style>
</head>

<body>
    <main>

        <header class="header">666</header>
        <nav class="caidan">
            <ul class="caidan_ul">
                <li class="caidan_li">
                    <nav>
                        <div class="caidan_img" id="zhuye_img"></div>
                        <a class="a_zhuye" href="#">主页</a>
                    </nav>
                </li>
                <li class="caidan_li">
                    <nav>
                        <div class="caidan_img" id="boke_img"></div>
                        <a class="a_boke" href="#">写博客</a>
                    </nav>
                </li>
                <li class="caidan_li">
                    <nav>
                        <div class="caidan_img" id="leixing_img"></div>
                        <a class="a_leixing" href="#">文章类型</a>
                    </nav>
                </li>
                <li class="caidan_li">
                    <nav>
                        <div class="caidan_img" id="shezhi_img"></div>
                        <a class="a_shezhi" href="#">设置</a>
                    </nav>
                </li>
            </ul>
        </nav>
        <div class="zuo">
                
                        <div id="nav">
                            <ul  class="aaa">
                                <li><a href="#">首页</a></li>
                                <li class="navmenu"><a href="#">JavaCore</a>
                                    <ul>
                                        <li><a href="#">java基础</a></li>
                                        <li><a href="#">jdbc</a></li>
                                    </ul>
                                </li>
                                <li class="navmenu"><a href="#">JavaWeb</a>
                                    <ul>
                                        <li><a href="#">html</a></li>
                                        <li><a href="#">css</a></li>
                                        <li><a href="#">js</a></li>
                                    </ul>
                                </li>
                                <li><a href="#">前端技术</a></li>
                                <li><a href="#">框架</a></li>
                            </ul>
                        </div>
                  
        </div>
        <div class="zhong">2</div>
        <div class="you">3</div>
        <footer class="footer">00</footer>

    </main>
</body>

</html>